Coma is a state of unconsciousness in which the patient is incapable of being awake, and is unarousable, even with vigorous stimulation. Coma is a self-limiting state which is usually the result of disease or injury and rarely lasts for more than 4 weeks. While comatose, a patient may be reflexive to painful stimuli but lack the ability to demonstrate localized response or defensive movements (Posner et al. 2007).
The diagnosis of patients in coma is clinical and involves examination of physiological functions, including arousal, pupillary responses, respiration, motor function, and reflexes. Several clinical features of coma include the loss of spontaneous or induced arousal, no eye opening, and the absence of sleep-wake cycles on EEG (Giacino et al. 2014). Several diagnostic scales are available for severity rating and include the Glasgow Coma Scale (Teasdale and Jennett 1976) and the FOUR Score (Wijdicks et al. 2005).
References and Readings
- Posner, J. B., Saper, C. B., Schiff, N. D., & Plum, F. (2007). Plum and Posner’s diagnosis of stupor and coma. New York: Oxford University Press.Google Scholar